1. Field of the Invention
This invention relates to a drum type paper stock refine screen which is used for removing foreign matter from a paper stock which serves as a paper-making material.
2. Related Art
A paper stock serving as a paper-making material, particularly a paper stock composed of a waste paper pulp which is macerated by a pulper is mixed therein with foreign matter such as, for example, resin chips caused by a binding string, tar particles, metal foreign matter such as metal binding devices, and the like.
Heretofore, it has been known to use a cyclone device, a vibrating device, a centrifugal separating device or the like as a device for obtaining a refined paper stock by removing foreign matter from the paper stock.
On the other hand, patent material 1, which is the Official Gazette of Japanese Patent No. 3231748 and which is owned by the present applicant, provides a paper stock washing device in which a paper stock is put into a lateral rotary drum, wherein the paper stock is then repeatedly raked up by a raking fin which is disposed at the inner peripheral surface of the rotary drum and allowed to drop in accordance with rotation of the rotary drum, and wherein ink component in the paper stock is filtrated and dewatered through air and water passage apertures which are formed in the drum peripheral wall.